Anonymous
Anonymous asked in Science & MathematicsAstronomy & Space · 1 decade ago

# A giant hole through the earth. Would you float in the middle?

Let's say there is a giant hole all the way through Earth

1st)If you jumped in would you fall back and forth until you eventually came to the center

2)or if there was a ladder and you climbed down, would you just float in the center or would you be crushed by gravity into a little ball of mass?

Now, I assume strange stuff to begin that you probably can't have any of this with no center of gravity? But if it's possible to put that aside

Or, there for what would happen to earth if they did drill a hole from one side through the other and there was no center of gravity, would the planet just fall into space?

and if so would it be right at the moment you dug at the center?

Really, I just want to know the 2nd) scenerio if you would float or be crushed and there is some super mega metal wall so no burning up from heat or anything

just gravity curiousity

Relevance
• Gary H
Lv 6

1) No, but if you sealed the ends of the hole and vaccuumed out the air, you could bounce back and forth indefinitely

2)No, gravity is max right here on the surface, and decreases as you go down. But you would not be strong enough to overcome the bouyant forces of denser air to climb down much further than about 50 miles.

3) No, constructing such a hole, tho a monumental (and valuable) feat, would not cause any harm to the planet.

[Long explanation, my response to a previous posting of this question]

If you were in a hollow sphere in the exact center of Earth, the mass of Earth would be evenly distributed around you, therefore also the gravitational forces generated. If the sphere were small compared to your body size, you'd experience microgravity (weightlessness), similiar to aboard an unaccelerating spaceship. If the sphere were much larger than your body size, you'd feel a slight tugging toward the nearest wall of it, i.e, you'd exhibit a weight of grams or ounces, depending on the size of the sphere, being completely weightless only when you were in the exact center of the sphere.

Yes, if you jumped into such a well you would have to climb or be lifted out:

There's air in the well. Terminal velocity for a human in Earth freefall is in the range of about 100 (if your fall flat, arms and legs extended) to 200 miles per hour (if you "dive", body and limbs straight). If it weren't for the fact that the density of the air wouldn't be constant with depth, you'd maintain close to this speed for the first few hours (remember, it's 4000 miles to the center from here), until you were deep enough that a significant percentage of the mass of Earth was behind you. Then you'd gradually begin slowing down due to air friction versus the decreasing net gravitational force on you. After a couple of days of this, you'd be approaching the center of Earth at about the same speed as a feather falling through the air.

But if you factor into your well the fact that air pressure will increase by a factor of about 10 for every 10 miles down you go, you'll figure that you're going to have real trouble even get close to the center. The reasoning is this: at sea level, the volume of air equal to the volume of a person (about 3 cubic feet maybe) weighs about 0.006 pounds. Every 10 miles down you go, that same volume will weigh 10 times more. If I have it figured right (anyone out there???), somewhere between about 40 and 50 miles down the air density will equal that of water. You will float at that point just as if you were in water. Swimming down much further will be increasingly difficult since unlike water, the density of the air will still keep increasing with depth, making your bouyancy progressively more difficult to overcome.

The only way to be able to fall all the way to the center would be to seal and apply vacuum to your well. Then when you jumped in with your spacesuit on, no air or air friction will slow you down. If the vacuum was close to perfect, you'd accelerate at a 1G rate to thousands of miles per hour within minutes (100 seconds at 1G = 32ft/sec^2 =3200ft/sec~= 0.6mps=2182mph), Gradually, this rate of acceleration will decrease as more of the mass of Earth becomes behind you, becoming 0 as you pass through the center, then gradually tending to reverse your acceleration to the point where your speed would be zero just about time you hit surface level on the opposite side (you did dig ALL the way through, right?). Then you would start falling back again, and if your vacuum were perfect, continue this cycle indefinitely.

Ok first of the earth's magma outer core spinning around the earth's solid inner core causes the earth's em field or (electro- magnetic field) that keeps out all the suns radiation. If you drilled a hole to the middle of the earth you would disrupt the magma flow and hence destroy the em field. will this field down we would be hit full force by the suns radiation and be fryed. If you get by that there is a possibility that because of the huge amount of gravity being pushed on to a now unstable core that the earth could implode. Again if you get by that you have to worry about the pressure of millions of tons of rock before you even get to the core so in all likeliness i say you would probably die before you even get there. But again if you managed to reach the inner core the heat would be about 1/2 the temp of the sun and would melt even your bones. But since you drilled a hole through the core you created a vacuum much like space which in the middle would have zero gravity.

Gravity is strangely weak.

Lets, our muscles overcome the gravity of the entire Earth.

A simple magnet can do this also.

Gravity is 10^39 times weaker than the electro-magnetic force.

Anyway, if you positioned yourself in the Earth, such that the gravity from the surrounding rock (Earth) was the same in all directions, yes, you would "float" there.

No crushing would occur.

How could it, you don't get crushed when standing on top of the Earth.

Gravity is just far too weak.

A possible explanation for the weakness of gravity is given in M-theory.

See here for a really good documentry on string theory which covers this:

http://www.pbs.org/wgbh/nova/elegant/program_d.htm...

It's very very good.

At the center of the earth, you would not feel any gravity. This is

because the gravitational pull from every region of the earth is exactly

counteracted by the gravitational pull from the corresponding region on the

opposite side of you. This all adds up to a great bug zero.

Of course, you would perish in molten lava long before you reached the

center of the earth, but that's a different matter.

• cosmo
Lv 7

Inside a spherical cavity at the center of the Earth, you would feel no gravitational force anywhere inside the cavity. That is, you wouldn't be pulled toward the wall if you drifted a little from the center. This is true of the gravitational force inside any homeid (that is, a shell whose inner and outer boundaries are similar ellipsoids, similarly oriented).

There would, however, be a gravitational effect: time would progress slightly more slowly than it does outside the Earth. This is a general relativistic effect.

You would fall at a decelerating rate past the center and oscillate back and forth until you stopped at the center.

If you climbed down a ladder you would become lighter as you approached the center.

When you climbed back out you would continue to get heavier as you left the center and neared the surface.

• Labsci
Lv 7

You would be pulled to the side of the hole as you were falling. It is unlikely you could fall into the centre, because you would be closer to one side, which would attract you. You would therefore fall into the hole, but as you approached the hollow core, the gravity from the mass of the Earth, that is the edge of the centre cavity, would attract you.

If you were somehow placed into the centre cavity, then you would probably just experience weightlessness, the pull of the Earth is not enough to pull us apart now, so it should not be strong enough then, either. If you moved closer to one edge of the cavity, then the gravity from that closer portion of the edge would draw you to it, and you would fall toward it.

• eggman
Lv 7

Since the mass of the earth would be more or less evenly distributed in all directions around you, you would indeed float as if you were in orbit. Too bad all the molten Iron and Nickel would burn you to a crisp long before you could reach the center.

• Gene
Lv 7